Investors, not yet convinced that the buying opportunity of a lifetime has arrived, sent stocks tumbling on Monday to their lowest levels in more than 11 years amid a growing crisis of confidence in the government's ability to fix the ailing financial system.

Announcements about who would be in charge of President Obama's economic strategy at first sparked powerful stock rallies on optimism a new direction would help snap the economy out of its slump and boost confidence in banks. However, details of the stimulus and bank bailout didn't live up to Wall Street's lofty expectations. The result: Sell-offs have left stocks near bear market lows.

With little question the U.S. is in the grips of a recession, investors this week will lean on a stream of earnings and economic reports to help determine exactly how prolonged and painful the downturn might be.

With little question the U.S. is in the grips of a recession, investors this week will lean on a stream of earnings and economic reports to help determine exactly how prolonged and painful the downturn might be.

Warren Buffett, dubbed the Oracle of Omaha by Wall Street, is making his voice heard these days. The billionaire investor is out talking to cable TV anchors. To magazines. To shareholders. To Congress. To foreign investors. To a former Wall Street analyst who is writing a book about him.

Investors have already seen some of the financial market fallout caused by indebted homeowners defaulting on their mortgages and banks losing billions of dollars from bad bets on securities tied to risky mortgages. Shares of banks, mortgage lenders and retailers have suffered their own private bear-market pain.

If you haven't yet felt the impact of the nation's credit crisis, just wait. Chances are, you won't have to wait long. So far, the turmoil may feel a bit remote for average people: Failed mortgage lenders. Gargantuan write-downs by banks. Foreclosures for people who couldn't really afford the mortgages they got. Are the rest of us in danger? Quite likely, yes.